In the study, several screening questions were used to measure maternal drinking behaviour; how many drinks were needed to feel high, had others irritated or hurt them by criticising their alcohol consumption, had they felt they ought to drink less alcohol, and had they ever drunk alcohol in the morning to relieve a hangover.
The study shows that risk drinking before pregnancy increases the risk of early behaviour problems among children. According to the researchers, risk drinking may be due to other associated risk factors in maternal behaviour such as anxiety, depression or attention deficit hyperactivity disorder (ADHD), which also are known to have an impact on child behavioural problems.
Prenatal exposure to alcohol is known to affect the developing foetus, with adverse cognitive and behavioural effects. Most risk drinking women therefore limit or stop drinking alcohol while pregnant. Paternal risk drinking is also known to have a negative impact on toddler behaviour. This is the first study to study the impact of risk drinking before pregnancy. The results could not be explained by alcohol consumption during pregnancy and after birth.
“This increased risk for behavioural problems in the child is probably not due to the risk drinking per se, but rather to the general mental health and lifestyle of some of the mothers. Risk drinking behaviour before pregnancy may indicate that these families could need closer follow-up and support during the early years of the child’s life” says Ann Kristin Knudsen, primary author of the article published in the European Child and Adolescent Psychiatry journal.
The study considered both internalising and externalising behavioural problems among the toddlers. Internalising behavioural problems include anxiety, inhibition, withdrawal or depression. Restlessness, defiance, fighting and lack of remorse are examples of externalising behaviour. These are known risk factors for behaviour problems in childhood and adolescence, which sometimes continue into adulthood.
The MoBa study is the largest birth cohort study in the world, with more than 109,000 children, 91,000 mothers and 71,700 fathers enrolled. The mothers are asked to complete regular questionnaires about the development and lifestyle of each child and their own general health. This sub-study used data collected at 17 weeks of pregnancy and when the child was 18 months and 3 years old. Data from 56,682 questionnaires were included for the 18-month-olds and from 46,756 questionnaires for the 3-year-olds. The questionnaires included standard behavioural and screening checklists.
Further research is needed to understand the mechanisms between pre-pregnancy drinking and toddler behaviour problems.
What is risk drinking?
Use of alcohol in a way that increases the risk of
- harmful consequences for the user or others, physically or mentally
- alcohol dependency
- social, financial, legal or relationship problems
Risk drinking can be defined both by alcohol consumption and by drinking patterns and behaviour related to alcohol use. For women, risk drinking is usually defined as more than three alcohol units at any drinking occasion, compared to four units for men.
Drinking patterns may include:
- drinking alone
- a negative change of feelings or personality when drinking alcohol
- drinking at inappropriate times, such as in the morning or at work
- drinking more or faster than others
Maternal pre-pregnancy risk drinking and toddler behaviour problems: the Norwegian Mother and Child Cohort Study. AK Knudsen et al. Eur Child Adolesc Psychiatry 2014, doi: 10.1007/s00787-014-0588-x.